1. Field of the Invention
Present invention relates to an improvement of lock security mechanism of connector to be used for the connection of electric wires or the like.
2. Description of Prior Art
Usual lock security mechanism of electrical connector, such as shown in FIGS. 6 & 7, is provided with a locking arm 3 extending forwardly of the outer wall 1 in a male housing M by means of front upright base 2. A female housing F has a shell 6 receiving the male housing M and having a locking chamber 7 into which the locking arm 3 is inserted. When both housings are engaged with each other, an engaging claw 4 at an end of the locking arm is engaged with a securing hole 8. In this locking state, an unlocking preventing piece 9 is detachably inserted between the outer wall 1 and the locking arm 3 so that the locking state may be prevented from unintentional release. In the drawings, 5 is receiving rooms for terminal fittings not shown. Such arrangement is found in Japanese Utility Model Preliminary (laid-open) Publication No. 59-29351.
Prior art locking security mechanisms as such have an arrangement that the unlocking preventing piece 9 is attached after the male and female housing M, F are engaged with each other. Therefore, it has often occurred that during the engagement operation the insertion of the unlocking preventing piece 9 is omitted and the omission is difficult to be found later. Further, as clearly shown also in the drawings, the unlocking preventing piece 9 may be mounted before the male and female housings M, F are engaged together. In this case, any undesired state that both housings are placed in a incomplete locking position cannot be found easily. Moreover, the unlocking preventing piece 9 which is small and separate from the housing is apt to be released in case of inspection or exchange of the connector. Such a released piece is difficult to be found out in the engine room of a motor-car or the like location if lost.